Research On Performance Matching Of Two-speed Hydraulic Chassis For Wheeled Milling Machine

In this paper, the present situation about drive systems of domestic and exported construction machinery as well as the drive system of wheeled milling machine have synthetically been analyzed. The necessity and feasibility about research on performance matching of two-speed hydraulic chassis for wheeled milling machine have also been given. Through analyzing the wheeled milling machine travelling theory, based on slip efficiency of all-wheel drive vehicle and kinematics equations of hydraulic drive vehicles, the principle that control system pressures between the front wheels and the rear wheels to meet the traction matching has been worked out. Another principle that control system flow according to the variety of the system pressures to meet the speed matching between the front wheels and the rear wheels has also been researched. On this basis, the overall program of hydraulic drive system for two-speed hydraulic chassis has been designed, the main components has been chosen, and the efficiency of the hydraulic systems has also been analyzed theoretically. The results show that hydraulic systems of the front wheels and the rear wheels are with high efficiency.The electro-hydraulic proportional constantly pressured variable pump, composed of an electro-hydraulic proportional relief valve and a constantly pressured variable pump, has been theoretically analyzed and its mathematical model has also been set up. Based on the software AMESim, the hydraulic drive system model of two-speed hydraulic chassis for wheel milling machine has been set up and the simulation for its performance has also been carried on. Simulation results show that by controlling the system pressures of the front wheels and the rear wheels on basis of the external load their traction reasonable matching can be reached; The hydraulic drive system of the rear wheels can automatically change its flow in accordance with its pressure variety, to ensure the speed synchronization of the front wheels and the rear wheels. Feasibility of the above program is verified. At the same time, the research method applied in the paper is suited for hydraulic drive systems of other construction machinery.